Wireless input devices like wireless mouse devices and wireless keyboard devices are commonly used input tools for computers. FIG. 1 shows a schematic diagram of a conventional wireless input device 13 for inputting data to a computer host 11, and which comprises a radio frequency (RF) transmitter 131, a sensing unit 132 and a battery 133. Input signals, such as signals input by a mouse or by a keyboard sensed by the sensing unit 132, are modulated by the RF transmitter 131, and are transmitted to an RF receiver 12 and then to the computer host 11. Electric energy required by the RF transmitter 131 and the sensing unit 132 is provided by the battery 133.
However, since the RF transmitter 131 is quite power-consuming, the battery 133 is easily used up and thus needs to be frequently replaced, resulting in not only environmental-unfriendly effects but also usage inconveniences.